The invention relates to an aircraft air-conditioning system and a process for working an aircraft air-conditioning system.
The cabin of a modern commercial aircraft is normally divided into different air-conditioning zones which are supplied with air-conditioning air as required by an air-conditioning unit of the aircraft. Typical air-conditioning zones of an aircraft cabin are, for example, a first class area, a business class area and an economy class area. The operation of an air-conditioning unit of the aircraft air-conditioning arrangement is normally controlled according to the cooling requirement of the air-conditioning zone with the highest cooling requirement, i.e., the air-conditioning unit provides cooled process air at a temperature which is sufficiently low to cool the air-conditioning zone with the highest thermal load generally the economy class area of the cabin—to a comfortable temperature. For example, the operation of the air-conditioning unit is controlled in such a way that it provides cooled process air at a temperature of 11° C.
To also enable a comfortable temperature to be set in air-conditioning zones with a lower thermal load, an appropriate quantity of hot engine bleed air is mixed with the cooled process air provided by the air-conditioning unit before the air is finally blown into the air-conditioning zone. As an alternative to this, the cooled process air provided by the air-conditioning unit can be heated to the desired temperature by means of an electric heating device before being supplied into an air-conditioning zone. These circumstances are described for example in EP 1 701 884 B1 or U.S. Pat. No. 7,802,732, B2.
Working areas which are provided in the door areas of the aircraft cabin and in which the on-board kitchens, the so-called galleys, of the aircraft are also arranged, are cabin areas with a particularly low thermal load since there are normally only a few people in these areas. Moreover, cooled galley areas, which serve for example for storing foodstuffs provided for distribution to the passengers of the aircraft, give off cooling energy to the environment. Finally, cooling energy is also supplied to the working areas of an aircraft cabin by way of cold interior surfaces of the aircraft doors. The air-conditioning air supplied to the working areas of the aircraft cabin by the aircraft air-conditioning arrangement therefore also normally has to be heated by means of appropriate heating devices, such as those described in EP 1 701 884 B1 or U.S. Pat. No. 7,802,732, to a considerably higher temperature than the temperature of the cooled process air provided by the air-conditioning unit of the aircraft air-conditioning arrangement in order to enable a comfortable ambient temperature to be set in the working areas of the aircraft cabin.